Computational Docking as a Tool in Guiding the Drug Design of Rutaecarpine Derivatives as Potential SARS-CoV-2 Inhibitors.

COVID-19 continues to spread around the world. This is mainly because new variants of the SARS-CoV-2 virus emerge due to genomic mutations, evade the immune system and result in the effectiveness of current therapeutics being reduced. We previously established a series of detection platforms, comprising computational docking analysis, S-protein-based ELISA, pseudovirus entry, and 3CL protease activity assays, which allow us to screen a large library of phytochemicals from natural products and to determine their potential in blocking the entry of SARS-CoV-2. In this new screen, rutaecarpine (an alkaloid from Evodia rutaecarpa) was identified as exhibiting anti-SARS-CoV-2 activity. Therefore, we conducted multiple rounds of structure-activity-relationship (SAR) studies around this phytochemical and generated several rutaecarpine analogs that were subjected to in vitro evaluations. Among these derivatives, RU-75 and RU-184 displayed remarkable inhibitory activity when tested in the 3CL protease assay, S-protein-based ELISA, and pseudovirus entry assay (for both wild-type and omicron variants), and they attenuated the inflammatory response induced by SARS-CoV-2. Interestingly, RU-75 and RU-184 both appeared to be more potent than rutaecarpine itself, and this suggests that they might be considered as lead candidates for future pharmacological elaboration.

The Ethanol Extract of Evodiae Fructus and Its Ingredient, Rutaecarpine, Inhibit Infection of SARS-CoV-2 and Inflammatory Responses.

COVID-19, derived from SARS-CoV-2, has resulted in millions of deaths and caused unprecedented socioeconomic damage since its outbreak in 2019. Although the vaccines developed against SARS-CoV-2 provide some protection, they have unexpected side effects in some people. Furthermore, new viral mutations reduce the effectiveness of the current vaccines. Thus, there is still an urgent need to develop potent non-vaccine therapeutics against this infectious disease. We recently established a series of detecting platforms to screen a large library of Chinese medicinal herbs and phytochemicals. Here, we reveal that the ethanolic extract of Evodiae Fructus and one of its components, rutaecarpine, showed promising potency in inhibiting the activity of 3C-like (3CL) protease, blocking the entry of the pseudo-typed SARS-CoV-2 (including wild-type and omicron) into cultured cells. In addition, inflammatory responses induced by pseudo-typed SARS-CoV-2 were markedly reduced by Evodiae Fructus extract and rutaecarpine. Together our data indicate that the herbal extract of Evodiae Fructus and rutaecarpine are potent anti-SARS-CoV-2 agents, which might be considered as a treatment against COVID-19 in clinical applications.

The water extract of Aloe vera prevents fluoxetine-induced multiple-drug resistance of E. coli by inhibiting reactive oxygen species formation and membrane permeability.

BACKGROUND: The medication of synthetic chemical is one of the main treatments for depressive disorders. Different lines of evidence reveal that a long-term exposure to anti-depressants, e.g., fluoxetine, is causing multiple-drug resistance (MDR) of gut microbiomes. The MDR bacterial strains in gut pose a threat to intestinal balance and treatment of future microbial infection. Effective strategies are thus in urgent need to prevent the anti-depressant-mediated MDR of gut microbes. PURPOSE: We aimed to investigate the potential role of Aloe vera (L.) Burm. f. (aloe; Liliaceae family) to prevent MDR of E. coli being co-cultured with fluoxetine. METHODS: The extract of A. vera was co-cultured with E. coli and fluoxetine to analyze the preventive effect of MDR. To figure out the mechanistic action, the formation of reactive oxygen species (ROS) and the expression of key biomarkers, including outer membrane proteins (OmpF and OmpC), superoxidative stress activator (SoxS) and efflux pumps (AcrA/B-TolC), were determined in E. coli being treated with fluoxetine and aloe extract. In addition, the genetic mutation of transcriptional factors of these biomarkers was determined in the fluoxetine-treated E. coli. RESULTS: The water extract of A. vera showed considerable potential to reduce the number of fluoxetine-mediated MDR colonies. The extract robustly suppressed the formation of ROS in E. coli. However, thiourea and N-acetylcysteine, two well-known antioxidants, showed no activity in preventing the formation of bacterial MDR. Additionally, A. vera extract directly affected the fluoxetine-triggered early stress response of E. coli and the expression of downstream genes. Meanwhile, A. vera extract was able to inhibit the genetic mutation of SoxR gene in E. coli, as induced by co-cultured with fluoxetine. By fractionation of the aloe extract, the ethanol precipitate, composing mainly polysaccharides, showed robust activity in preventing the fluoxetine-mediated MDR. CONCLUSION: This study therefore suggested that the extract of A. vera could be an adjuvant agent to combat bacterial MDR during anti-depressant treatment.

The Extracts of Polygonum cuspidatum Root and Rhizome Block the Entry of SARS-CoV-2 Wild-Type and Omicron Pseudotyped Viruses via Inhibition of the S-Protein and 3CL Protease.

COVID-19, resulting from infection by the SARS-CoV-2 virus, caused a contagious pandemic. Even with the current vaccines, there is still an urgent need to develop effective pharmacological treatments against this deadly disease. Here, we show that the water and ethanol extracts of the root and rhizome of Polygonum cuspidatum (Polygoni Cuspidati Rhizoma et Radix), a common Chinese herbal medicine, blocked the entry of wild-type and the omicron variant of the SARS-CoV-2 pseudotyped virus into fibroblasts or zebrafish larvae, with IC50 values ranging from 0.015 to 0.04 mg/mL. The extracts were shown to inhibit various aspects of the pseudovirus entry, including the interaction between the spike protein (S-protein) and the angiotensin-converting enzyme II (ACE2) receptor, and the 3CL protease activity. Out of the chemical compounds tested in this report, gallic acid, a phytochemical in P. cuspidatum, was shown to have a significant anti-viral effect. Therefore, this might be responsible, at least in part, for the anti-viral efficacy of the herbal extract. Together, our data suggest that the extracts of P. cuspidatum inhibit the entry of wild-type and the omicron variant of SARS-CoV-2, and so they could be considered as potent treatments against COVID-19.

Polygoni multiflori radix extracts inhibit SARS-CoV-2 pseudovirus entry in HEK293T cells and zebrafish larvae.

BACKGROUND: Globally, COVID-19 has caused millions of deaths and led to unprecedented socioeconomic damage. There is therefore, in addition to vaccination, an urgent need to develop complementary effective treatments and/or protective and preventative therapies against this deadly disease. METHODS: Here, a multi-component testing platform was established to screen a library of herbal extracts from traditional Chinese medicine (TCM), to identify potent herbal extracts/phytochemicals as possible therapeutics for COVID-19. We utilized assays for spike protein (S-protein) binding to angiotensin-converting enzyme II (ACE2); the enzymatic inhibition of 3CL protease; and entry of the SARS-CoV-2 pseudovirus into cultured HEK293T cells and zebrafish larvae. RESULTS: Over a thousand herbal extracts were screened and approximately 20 positive hits were identified. Among these, we found that the water and ethanol extracts of Polygoni Multiflori Radix (PMR) significantly inhibited S-protein binding to ACE2, 3CL protease activity, and viral entry into the cell and fish models. The water extract was more effective than the ethanol extract, with IC50 values of 25 to 500 µg/ml. In addition, the polysaccharide-depleted fraction of the former, and epigallocatechin gallate (EGCG) which was found in both extracts, displayed significant antiviral activity. CONCLUSIONS: Our results indicate that the water and ethanol extracts of PMR have an inhibitory effect on SARS-CoV-2 pseudovirus host-cell entry. Furthermore, EGCG might be an active component of PMR, which blocks SARS-CoV-2 entry to cells. Taken together, our findings suggest that PMR might be considered as a potential treatment for COVID-19.